Fillers influence on the mechanical properties of the composite bone cements
Jerzy Włodarski*, Janusz Szyprowski**, Wojciech Więckowski***, Arkadiusz Szarek*** *Politechnika Częstochowska, Wydział Inżynierii Mechanicznej i Informatyki, Instytut Obróbki Plastycznej, Inżynierii Jakości i Bioinżynierii al. Armii Krajowej 19c, 42-200 Częstochowa **Wojewódzki Szpital Specjalistyczny w Częstochowie, ul. Bialska 104/118, 42-200 Częstochowa ***Politechnika Częstochowska, Wydział Inżynierii Mechanicznej i Informatyki, Instytut Obróbki Plastycznej, Inżynierii Jakości i Bioinżynierii al. Armii Krajowej 19c, 42-200 Częstochowa
Quarterly No. 4, 2005 pages 78-81
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abstract The first use of PMMA (methyl polymethacrylate) in a hip joint alloplasty was at the early 60’s when Charnley anchored the hip joint endoprosthesis inside the femur. Surgical cement, being the polymer composite, sets creating the element bonding prosthesis with a bone, and thus, it is required to be highly biocompatible and biotolerant. Clinical research indicates many reservations regarding bone cements, starting from the relatively high temperature during polymerization (after 4÷6 minutes of polymerization the temperature grows up to 55÷80°C or even up to 125) through mechanical and fatigue properties and ending with high degradation and particle emission to the organism. The tests carried out all over the world are aimed towards the improvement of the bone cements properties. Nowadays many kinds of cements are used either as pure polymer or with admixtures of different substances. Application of fillers is of a great significance to the mechanical properties of the PMMA. Specificity of the working conditions forces the necessity of transition of extremely complex loading resulting from human motor activity. Working environment of the cement is highly aggressive dramatically increasing the ageing rate and causes higher enucleating of the cement, weakening the bone-cement-implant system. This phenomenon can lead to endoprosthesis loosening and to the necessity of reimplantation procedure. Another negative effect of the cement ageing and spalling is the phenomenon of cement particles emission into the organism. These particles, moving inside the organism, settle inside different organs i.e. liver, kidneys etc. causing pathologies. Microstructure of the SIMPLEX P cement is shown in Figure 1, structure changes influenced by different additives can be observed in Figures 2 and 3. The research performed at the Institute of Metal Working, Quality Engineering and Bioengineering permits to determine the influence of the fillers on mechanical properties of bone cements, decrease in polymerization temperature and decrease the ageing process rate of the acryl cements. The results of compression test of SIMPLEX P with 5% of different fillers is presented in Figure 4. The sample chart of the compression test of SIMPLEX P with 5% of BIO-OSS additive is given in Figure 5. Irish HOWMEDICA LIMERICK SIMPLEX P cement was taken to the tests. The package includes polymer powder and monomer liquid is sterile. Three kinds of fillers were taken into tests: bone-substitutive material BIO-OSS, bovine bone pulp and Al2O3. Differences in mechanical properties and in structure of bone cement are of significant influence on life and mechanical properties of the bone cement. Key words: composite, mechanical proprieties, bone cements